Flotation of silicates from titaniferous iron ores



2,904,177 Patented Sept. 15, 1959 FLOTATION F SILICATES FROM TITANIFEROUS IRON ORES Eugene J. Michal, Metuchen, N.J., assignor to National Lead Company, New York, N.Y., a corporation of New Jersey No Drawing. Application May 29, 1957 Serial No. 662,322

4 Claims. (Cl. 209-166) This invention relates in general to the treatment of a titaniferous iron material. More specifically, it relates to a flotation method for the removal of silicates from a titaniferous iron ore.

Many methods have been used in the past for separating the silicates and other constituents from the titanium bearing materials in a titaniferous iron ore. Among the most useful methods are flotation processes in which the silicates are separated from the titanium values by adding anionic type promotors to the ore and floating ed the titanium values from the silicates. This operation is usually carried out under neutral or slightly alkaline conditions. The most useful anionic type promotors are oleic acid, fish oil, fatty acids, resin or naphthenic acids and the like.

Although these methods have met with some success when processing various types of ore, however, these processes are not too successful with ilmenite ores since the ilmenite fraction often constitutes the bulk of the ore and has to be floated away from the silicate values. Since the silicate portion of an ilmenite ore is, in many instances, less than the ilmenite fraction, it would be desirable to employ a process where the silicate portion is removed by flotation from the ilmenite values.

An object of the instant invention, therefore, is to provide a simple and economical method for separation of silicates from ilmenite ore. A further object is to provide a straightforward flotation method for the separation of silicates from the ilmenite values. These and other objects will become apparent from the following more complete description of the instant invention.

Broadly, this invention contemplates a process for separating silicates from the titanium values in an ilmenite ore which comprises grinding the ore to 60 mesh size, preparing an aqueous pulp with said ground ore, acidi fying said pulp to a pH between 3.0 and 6.0 by adding hydrofluoric acid, adding starch to said pulp to depress the titanium values adding to said pulp a cationic amine flotation agent and subjecting the treated pulp to a froth flotation whereby said silicates are removed by flotation from the residual titanium values.

The silicate portion of the ore which is to be removed by the flotation operation from the ilmenite portion usually consists of a number of mineral constituents. The most common of these silicates present in the ore are garnet, feldspars, hornblende and augite.

Ilmenite ores usually contain various amounts of these silicate constituents which cannot be removed by mechanical means such as grinding, magnetic separation, gravity concentration, and the like and, therefore a flotation process is useful. The flotation process of the instant invention is particularly desirable since the silicate, usually the smaller portion, is floated away from the ilmenite fraction.

In carrying out the process of the instant invention, the ilmenite ore containing the silicates to be removed was ground until the ore passed through a 60 mesh size screen. A pulp of the ground ore was prepared in water, the pulp density was 20% to 50% solids. If desired, the ground ore was deslimed before forming the pulp slurry in order to obtain a more complete flotation separation.

The ulp was acidified to a pH of 3.0 to 6.0 with;

either hydrofluoric acid or a mixture of hydrofluoric acid and sulfuric acid. During the flotation run further acid was added, if necessary, to maintain the acidity within the specified pH range. The presence of hydrofluoric acid is necessary to remove the feldspars and other silicates, however, for economy it is desirable to employ a mixture of hydrofluoric and sulfuric acids.

Starch was added to the acidified pulp to depress the ilmenite. Several typesof starches, such as arrowroot, wheat, tapioca, and corn, were satisfactory but potato starch seemed to be particularly effective. The starch was added for convenience as a one percent solution in amounts ranging from 0.5 to 20.0 pounds of starch per ton of ore.

After the ilmenite was depressed, a cationic amine flotation agent was added as a collector of the silicates in the ore. Illustrative examples of the cationic amine flotation agents which are particularly effective are higher aliphatic amines, such as lauryl amine, hexadecyl amine, dodecyl amine, short chain amines such as triethanol amine; amine salts which may be used include lauryl amine hydrochloride, hexadecyl, amine hydrochloride, and dodecyl amine hydrochloride; quaternary ammonium salts of the higher aliphatic series may be used such as cetyl trimethyl ammonium bromide, lauryl triethyl ammonium chloride and octadecyl trimethyl ammonium chloride. Commercial grade fatty amine acetates may be used such as Armac CD and Armac TD made by Armour and Company, or primary and secondary fatty amines such as Armeen CD and Armeen TD made by Armour and Company or a primary amine derivative of dehydroabietylamine such as rosin amine D acetate made by Hercules Powder Company. The fatty amine acetates, Armac CD and Armac TD are alkylammonium acetates having the general formula:

0 CH3( i-QNH3R The fatty amines, Armeen CD and Armeen TD are primary and secondary fatty amines having the following formulae: RzNH Secondary Amine Hr Primary Amine The molecular weights, melting points and composition of the amine content of these cationic agents are as follows:

The rosin amine D acetate identified as RADA made by Hercules Powder Company is the reaction product of acetic acid and dehydroabietylamine having the following structural formula:

CHa CHzNH;

. CH3 The am'ounnof collector-added shouldbe from 0.2 to 1.0 poun d per ton of ore treated. These cationic flotation agents usually act'as their own frother, however, pine oil'a'nd other 'frothers may be addedin addition if desired.-

After suflicient aeration arelatively clean separation between the silicateportion and the ilmenite portion was obtained.

If it is desired to further separate the two fractions from one another, the above operation may be repeated and a more complete separation will be obtained.

In order'to further illustrate the process of the instant invention, f the following examples are presented.

Example I An ilmenite concentrate had the following mineral composition:

Percent Ilmenite 87 Garnet I 4 Feldspar 2 Hornblende Y T 3 Augite 3 Sulfides- 0.5 Miscellaneous- 0.5

Includes mica' spinel, and unidentified minerals.

twice repulped with 2,000wml. ofr'waterand the .slimes were decanted.

After the desliming treatment, the ore residue in the flotation machine was made up to about 50% solids by addition of tap .water,.and .the following reagents were used in the flotation procedure:

3.6 lbs. hydrofluoric acid per ton of ilmenite concentrate 0.6 lb. sulfuric acid per ton of ilmenite concentrate 1.45 lbs. potato starch (1% water solution) per ton of ilmenite concentrate 0.70 lb. .RADA (Rosin ,Arnine D Acetate...Hercules Powder Co.) per ton of ilmenite concentrate.

To the 'ore slurry in the flotation machine were added 3;6 lbs. per-ton of hydrofluoric acid to bring the pH down to 3.5. The slurry was conditioned (agitated) for three minutes after which 1.3 lbs. per ton of starch were added, and conditioned for three. minutes. Next, 0.28 pound per ton of RADA was added and conditioned for five minutes. Air was admitted, and a froth carrying the silicate minerals was removed. At this stage the pH of the.pulp was about 4.0. Three further steps of reagent addition and froth flotation were carried out.

The firstiinvolved theaddition of 0.14 pound per ton of RADA only. The second, addition of 0.30 pound per ton of H 50 0.10 pound per ton of potato starch,

I 4 and 0.14 pound per ton of RADA. The third step was the addition of 0.30 pound per ton of H 0.05 pound per ton of starch, and 0.14 pound per ton of RADA.

At the end of the test the pH of the slurry was 3.5.

Only 3.4% silicates remained in the flotation tails which represented a 79% removal by the flotation process.

Example II Another ilmenite ore had the following mineral composition:

. Percent ilmenite 61.1 Feldspar 13.7 Hornble nde 13.7 Garnet n 5.5 Augite 4.6 Miscellaneous 1.4 Includes mica, spine], sulfides, and unidentified minerals.

. Eleven hundred grams of this ore were wet ball-milled ina steel mill at about 50 percent solids pulp'density to about percent min-us mesh. The milled slurry was addedto a laboratory flotation machine and water was added to make a pulp density of about 25 percent 1 solids.

To the agitated pulp were added the following reagents in the order listed:

3.5 pounds hydrofluoric acid per ton of ilmenite ore 2.0 pounds-potato starch (1% water solution) per ton of ilmenite ore 0.76 pound of-RADA (Rosin Amine D acetate Hercules Powder Co.) per ton of ilmenite ore 0.06 pound of, pine oil per ton of ilmenite ore Three minutesconditioning time was allowed after. each reagent addition. Air was admitted to the flotation machine and the mineral ;froth was removed.

The products of the test were as follows:

Weight Percent TiOz Product (grams) T101 distributlon Flotation t'roth 413 10. 6 13. 4 Flotation tailing.'. G62 42. 8 86. 6

Calculated head 1,075 30.4 100 This represented about a 75% removal of the silicate values by the flotation process.

Example Ill Another type of an ilmenite ore had the following mineral composition:

Flotation m1.

1 The 0.80 pound of RADA was added in three separate' increments with a conditioning period of three minutes after each addition.

Air was admitted to the flotation machine after eachof the three RADA reagent additions and the froth was removed. The products of the test were as follows:

Weight Percent Percent T102 (grams) T: Feo) distri- Product I bution Flotation tailing Calculated head This. represented about a.71% silicate removal by the flotation process.v i

:: Example IV Onethousand grams of the ilmenite concentrate described in,Exa mple I was discpulverized to about 60 nieshiand added to 2,500 mllof water in a laboratory flotation-machine. The mixture was agitated and then agitation stopped and the slurry allowed to settle for 1 we minutes; after which time the slimes or fines remaining in suspension were decanted. This procedure was repeated'twice' and after the third decantation suflicient water was, again added to make an agitated pulp density of about 30% solids.

The followingreag'ents were added to the agitated slurry in the order listed: L'Spo'un'dsQ f potato starch (1% watensolution) per ton of concentrate 2.4 pounds of hydrofluoric acid per ton of concentrate 2.0 pounds of Armeen TD (Armour & Co.) per ton of concentrate v I t 0.062 pound of pine oil per ton of concentrate One. minuteconditioning time was allowed between the additions of the several reagents. Air'was admitted to the flotation machine and theflfroth was removed.

" The products of the test were as follows:

Weight Percent Product (grams) T10:

Flotation troth 47 Flotation tails Calculated head The silicate removal by flotation was about 50%.

Example V 1.52 pounds potato starch (1% water solution) per ton of concentrate 2.4 pounds hydrofluoric acid per ton of concentrate 0.5 pound Armac CD (Armour and Co.) per ton of concentrate 0.062 pound pine oil per ton of concentrate 6 The 0.5 pound 'of Armac CD was added in three increments with conditioning after each addition.

One minute conditioning time was allowed between additions of the several reagents. Air was admitted to A the flotation machine and the froth was removed.

The products of the test were as follows:

Weight Percent T101 Product (grams) T10: distribution Flotation froth 23. 2 9. 5 Flotation tailing 800 49. 6 90. 5

Calculated head 980 44. 7 .100. 0

The silicate removal by flotation was about 79%.

. Example VI An ilmenite concentrate had the following mineral coniposition: t

Percent Ilmenite 83 Garnet 5 Feldspar 3 Hornblende & Augite 8 Miscellaneous 1 1 lncludes mica, spinel, sulfides and unidentified minerals] 4.36 pounds hydrofluoric acid per ton of concentrate 2.55 pounds potato starch (1% water solution) per ton of concentrate 0.655 pound of 50% water solution of RADA (Rosin Amine "D Acetate-Hercules Powder Company) per ton of concentrate 0.025 pound of pine oil per ton of concentrate The reagents were added in three steps, in the following order: 3.27 pounds of HF per ton of ore,'followed by one minute conditioning to give a pH of about 4.0 in

the slurry; 1.82 pounds of starch per ton of ore, fol lowed by two minutes conditioning; three additionsof 0.145 pound of RADA per ton of ore, with 30 seconds conditioning after each addition; and 0.73 pound of starch per ton of ore. Air was admitted, and a flotation froth removed. Thesecond stage of reagent addition was begun immediately, and 1.09 pounds of HF per ton of ore, 0.145 pound of RADA per ton of ore, and 0.025 pound of pine oil per ton of ore were added. Air was admitted and a second flotation froth removed.

.The third stage of reagent addition was immediately carried out and consisted of the addition of 0.072 pound of RADA per ton of ore. A third froth was removed by admitting air to the machine, and this completed the flotation.

The products of the test were as follows:

7 A.75% silicate ,-removal ,was obtained-in the silicate flotation step.

,Example VII Six hundred gramsof the ilmenite concentrate described in Example I were disc pulverizedto 60 mesh and added to 2,000'ml. of water in a laboratory flotation The reagents'were added in the order listed above, with 1-3 minutes conditioning-time between reagent additions. Air w a s admitted to.the flotation machine-and a froth removed.

The, products of the test were as follows:

. r. ,We1ght.. Percent T: Product (grams) T10; distri- 7 button Flotatlorrfroth;: 218' 37. 45 I 32.3 Flotation tailing 347 .49. 35 67. 7 Calculated head... 565 44.70 100.0

This represented about an 81% removal of the silicate minerals.

Example VIII Six hundred grams of the ilmenite concentrate described in Example I were disc pulverized to about 60 mesh and added to 2,000 mlwof water in a laboratory flotation machine.

Agitation was begun-and;the following reagents were added to the slurry in the order listed:

g Weight Percent T10: Product (grams) TiOr distributton Flotation froth 186 35:25 25.9 Flotation taillng. 378 49. 7 74. 1

Calculated head 564 44. 100.0

7 About 83% of the silicates were removed by flotation.- From the above description and by the examples-pie sented, it ,has clearly-been shown that eflicientsilicate removal from ilmenite ore has been obtained,by=utiliain3 the process of the instant invention. The. flotation process of the instant invention is articiiIarIyeQectiveQin removing the silicate values from an ilmenite ore because the lesser quantities of silicate minerals are floated away from the ilmenite values. With ilmenite ores and concentrates,- the silicate content is often much less thanthe ilmenite content and, therefore,.the process of the instant invention is more effective than-the prior art methods which remove by flotation the ilmenite portionrfrom the silicate" portion. The process of the instant inventionzis a simpleand economical operation which results ilZLGm-i cient removal of the silicate fractions.

While this invention has been described and illustrate by the examples shown, it is not intendedtobe strictly limited thereto, and other modifications and variations may be employed within the scope of the following claims.

I claim: 1. A method for separating silicates from the titanium values in a titaniferous iron ore which comprises grind-" ing the ore to mesh size, pulping theground (are in aqueous media, acidifying the pulp to apH between about 3.0 and 6.0 by adding thereto an acid solution containing an ionizable fluoride ion, adding starch to said acidified pulp to depress the titanium-values, adding to said pulp a cationic amine flotation agent in amount from 0.2 to 1.0 pound per ton of ore and subjecting the treated pulp to a froth flotation whereby said silicates are removed by flotation from the residual titanium values.

2. Method according to claim 1 in which the titaniferous iron ore is ilmenite ore.

3. Method according to claim 1 inwhich the pulp is acidified with a combination of hydrofluoric-acid and sulfuric acid.

4. Method according to claim 1 in which the amount of starch employed is from 0.5 to 20.0 poundsper ton of ore.

References Cited in the file of this patent UNITED STATES PATENTS 2,297,689 OMeara 0on6, 1942 2,410,021 De-Vaney Oct. 29, 1946 2,466,995 McMurray Apr.' 12,1949: 2,483,890 De Vaney Oct. 4,1949 2,666,588 Schack et al. Jan. 19, 1954 2,792,940 Baarson May 21, 1957 OTHER REFERENCES I Chang: Substituted Starches in Amine Flotation of Iron Ore, Mining Engineering, September 1954;1iagee 922-924. 

1. A METHOD FOR SEPARATING SILICATES FROM THE TITANIUM VALUES IN A TITANIFEROUS IRON ORE WHICH COMPRISES GRINDING THE ORE TO -60 MESH SIZE, PULPING THE GROUND ORE IN AQUEOUS MEDIA, ACIDIFYING THE PULP TO A PH BETWEEN ABOUT 3.0 AND 6.0 BY ADDING THERETO AN ACID SOLUTION CONTAINING AN IONIZABLE FLUORIDE ION, ADDING STARCH TO SAID ACIDIFIED PULP TO DEPRESS THE TITANIUM VALUES, ADDING TO SAID PULP A CATIONIC AMINE FLOTATION AGENT IN AMOUNT FROM 0.2 TO 1.0 POUND PER TON OF ORE AND SUBJECTING THE TREATED PULP TO A FROTH FLOTATION WHEREBY SAID SILICATES ARE REMOVED BY FLOTATION FROM THE RESIDUAL TITANIUM VALUES. 